Ink jet printers typically include a plurality of printheads supported in a moveable carriage. A platen is spaced from the printheads and supports the print media during the printing operation. A typical minimum distance between the printheads and the platen is 1.20 mm. This distance must be constant, within a tolerance, along the entire printing path of the printhead to obtain uniform printing.
Certain maintenance procedures for ink jet printers, such as carriage replacement or platen replacement, require that the printhead to platen distance be calibrated. A conventional method of calibrating the printhead to platen distance is to insert a block gauge between the platen and a part of the carriage. This method has several disadvantages. First, use of the block gauge requires that there be an accessible area for insertion of the block gauge beneath the carriage. Second, the block gauge necessarily will be displaced from the printheads, and thus there is no assurance that the spacing at the printheads will be the same as the spacing where the block gauge was inserted. Third, the technician holding the block gauge may hold the gauge at an improper angle, and thus cause errors in the calibration process. Finally, a block gauge requires that the technician feel when the gauge seizes, which also can introduce errors given the cramped area in which the tool is inserted.
Thus, there is a need for a more accurate and easier to use tool and method for calibrating the printhead to platen spacing in an ink jet printer.